How healthy we are in part depends on the many different exposures we've had over our life – including to physical, psychological and social factors. Chronic exposure to psychosocial stress – for example, poverty or other disadvantage – leads to prolonged strain on the body. This weathering can make us physically ill before our time and prematurely age us. So what is psychosocial stress, how does it harm our health and what can be done about it? To discuss, our chief executive Dr Jennifer Dixon is joined by:  Dr Michelle Kelly-Irving, a life course epidemiologist working on health inequalities and the social determinants of health. Michelle is a director at Inserm in Toulouse, part of France's National Institute of Health and Medical Research. Professor Nish Chaturvedi, Professor of Clinical Epidemiology at University College London and Director of the Medical Research Council Unit for Lifelong Health and Ageing. Show notes Kelly-Irving (2019). Allostatic load: how stress in childhood affects health outcomes. The Health Foundation.   Gustafsson et al (2011). ‘Socioeconomic status over the life course and allostatic load in adulthood: results from the Northern Swedish Cohort.’ Journal of Epidemiology and Community Health. 65: 986-992.   Guidi et al (2021). ‘Allostatic load and its impact on health: a systematic review.’ Psychotherapy and Psychosomatics. 90: 11-27.   McEwen & Stellar (1993). ‘Stress and the individual – mechanisms leading to disease’. Archives of Internal Medicine.153: 2093-2101  Tampubolon & Maharani (2018). ‘Trajectories of allostatic load among older American and Britons: longitudinal cohort studies.’ BMC Geriatrics. 255.